The EDS/SL emergency fire exit sign slave unit is a double-sided interior emergency escape route sign. Slave units are powered from a central battery store instead of having their own backup battery. The benefits of a system using slave units are; larger batteries are more cost effective, superior battery life and maintenance and testing are performed in a central location. The EDS/SL slave unit is fully tested and passed the 850°C hot-wire test, as defined by ICEL. This unit is suitable for incorporation into an emergency lighting system complying with BS5266-1:2005 and can be fitted with legends complying with the Health and Safety signs directive of 1996.